50 



I note the following differences and resemblances: habits iden- 

 tical, also form and size, no difference in color thus far noted until 

 half grown. The differences noted, besides color as above, are all 

 microscopical and yet sufficient to at once separate them. The 

 hairs on cretidactylas are shorter than on the other, and remotely- 

 plumose; under a magnifyiug power of from one hundred and fifty 

 to two hundred diameters this difference is marked, those of homo- 

 dactylus showing no spines, upon the other they are apparent; the 

 ends of the hairs are more acute in the latter than in the former; the 

 subdorsal papillae in the dark ones stand nearer together than in the 

 others; the minute papilla back of the substigmatal tubercle bears 

 but two or three hairs in the dark ones and three or four in the 

 light ones. Other differences of this nature have been noted. I 

 have no doubt that there are similar differences in the younger lar- 

 vae. It is surprising how nearly alike these preparatory stages of 

 two moths belonging to distinct genera prove to be. Color in this 

 case is a convenient difference as it affords the only ready means of 

 separating the larvae. 



The pupa of homodactylus measures .45 of an inch. It is light 

 pea-green, turning white before the moth escapes. There is a clear 

 dorsal space with an interrupted white line in the middle; also white 

 lines on the lateral faces. The tubercles are set with hairs exactly 

 as in the larvae so the pupa is quite conspicuously clothed; the head 

 and thorax support shorter hairs arising singly from the surface; 

 short, dusky hairs stand in rows on the wing covers apparently out- 

 lining the veins; there is a similar row on the antennae covers. The 

 pointed cremaster ends with many hooklets which fasten the pupa 

 securely to the leaf on which a tuft of silk has been spun by the 

 larva. The thorax is quite obliquely truncated; seen from below 

 it is slightly bilobed, rendered so by the prominent origin of the an- 

 tennae covers; between the lobes there is a slight, tufted tubercle. 



The pupa of cretidactylus has the same size and habits. Color 

 green ornamented with wine-colored and white lines. Tubercles 

 similar to the above. It is a little thicker, the anterior end more 

 obtusely truncated and less bilobed. The hairy clothing similar to 

 homodactylus, but hairs not so smooth as in that pupa. 



I have examples of both sexes of each species. Homodactylus 

 varies much and both varieties, a and b, of Walsingham appear 



